airbox mods

[illflem]

The true test of the Psycotty and pseudo psycotty will come when the weather gets warmer. I'm positive that they make a big difference from my own experience with lowered EGTs,especially when towing or running a highly bombed truck. Before I installed a Psycotty on my 3500 I had to back off on the throttle quite a bit towing 25k due to high EGTs,now with the Psycotty I rarely even need to look at the pyro.

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95' 25004X4,AT,Driftwood,Banks Stinger,Warn fender flairs and running boards(Play truck)95 3500,5 speed,Driftwood,Banks&Phscotty,34,000 GCVW apple and tractor hauler(work truck)

 

[joel]

Chad - a couple of points. First, intake air never goes past the turbine section of the turbo. Remember, there are 2 parts to the turbo; the turbine which is driven by hot exhaust gases and the compressor which takes intake air and compresses it. Second, cooler air does indeed provide more energy to a combustion process. Now, at what price for temp in a diesel engine I can't say. I'm not a deisel (or any other type besides amateur, really) mechanic.

What I do know is that in jet engines - essentially a big turbo with fuel injected into the end of the process - work FAR, FAR better in cool or cold air. How do I know this? I fly turbojet aircraft engines for a living and every single flight, we calculate performance numbers. Cold is better. Much better.

I would think the post compressor intake air temp is the important number here, not the ambient pressure air. Oh yeah, ram air will increase the pressure some, therfore providing more air/oxy molecules for combustion. The turbo compresses the intake air (don't know the ratio, thus can't compute the temperature rise) and (after being COOLED by the intercooler) stuffs it into the engine where it is compressed again by the piston stroke and, as we all know, that compression heats the air to a temperature that supports combustion. The intercooler allows more air/oxy molecules to go into the fixed volume of the cylinder (call it molucules/cubic inch). Again, I'd be interested in seeing the cylinder temp just before fuel injection and would guess it's a fairly stable number regardless of outside air temp - once the engine is up to operating temp, of course.

We tap air off the 12th stage of our compressor section for lots of functions in the plane. It's about 700F regardless of OAT, regardless of RPM and regardless of EGT. Now, I'm sure it fluctuates some, but we don't measure that particular parameter. My point is, all these temps are measurable and the process is a stable one. If the turbo spins at XX RPM, it provides compression at some ratio and therefore we can calculate the temp rise. Then we can apply the temp drop of the intercooler and the subsequent temp rise just prior to fuel being introduced. Not being a physics guy myself, I don't know the formulas without some research.

Bottom line is that cooler air provides more ENERGY for the combustion process and therefore more power. And the colder the air, the denser it is before we compress it (make it even more dense). One physics thing I do know is that air is compressable as long is its velocity is subsonic. There's a whole new set of rules for supersonic airflow.

By the way, if you want to see some of the physics stuff, check here.

[This message has been edited by joel (edited 12-16-2000). ]

 

[jkern]

joel

one word... AMEN!!! #ad
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i think that you summed up very well what i have been trying to say with the "colder is denser" thus more oxy molecules per given volume which equals more complete/better combustion which equals more power... noticable or not!!

thanks!

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Jeremy Kern
1999 2500HD 4x4 QC,SB, ISB, 5spd, 3. 54LSD, 33x12. 50 cooper STT's Denver off-road bumper with Ramsey RE12000, PIAA series 520, Rancho RS9000's, heavy ft. springs, and a bunch of other little things!

 

[jmeehan]

I'd love to run a Psychotty system for when I'm really getting on it, but when it's below freezing I don't want that much cold air going into an engine I'm trying to warm up. Older gas engines ran a dual system with a temp sensor and vacuum motor that switched the air intake from the heat stove on the exhaust manifold to ouside air as the engine warmed up. A similer system to this for our Cummins engines might be nice.

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'01. 5 2500 4X4 QC LB ETH/DEE SLT 3. 54, Patriot Blue

 

[drawson]

Here is some test I did late last summer when I was bored hauling some cattle.

EGT test using different air filters and configurations hauling cattle up a 5 ½ % grade 5. 6 miles long, two cows at a time. Tried to visually load cows so that the weight was the same. Outside temp (o/s) taken off in cab gauge. Cruise set at 65 MPH in 5th. EGT reading at the top of grade.

W/ stock housing and new paper filter (Fram) o/s 74 Deg EGT 1200+
with about one mile left had to kick the cruise off, down shift to 4th, and slow to 60 MPH to keep the EGT under 1200.

W/ stock housing and K&N filter o/s 78 Deg EGT 1100

W/ Open RE-0880 K&N filter o/s 80 Deg EGT 1050

W/ Psycotty housing w/ insulation tape and RE-0880 filter o/s 84 Deg EGT 900 - 925

There is also a big seat of the pants difference between the paper filter and a K&N in the Psychotty housing. The engine just feels freer to run with the bigger filter and the Psychotty housing.

 

[groundpounder]

Hey Chad and Joel, when, if ever would altitude come into the equation? And does dense air meen its heavier or thinner? I am trying to gain some sort of insight by relating it to high altitude. Air thats cold versed warm or hot. When hunting in high altitude is seems I can't find air to breath when its cold, however when its warm I can breath easier. If its thinner (when cold) does that mean there is less of it?

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99 Dodge 4x4 Quad Diesel auto. K&N, 4" JRE, 5" chrome tip, matched 275 Bosch injectors, 2. 5" Skyjacker leveling kit, Silencer ring MIA. (more to come)

 

[joel]

Altitude comes into the question all the time. At higher altitudes, you have less dense (thinner) air. It's all based on the weight of the atmosphere, actually. Here at sea level, you have the entire atmosphere weight giving us air pressure to breath, combust, etc. At 18,000', you have only half the weight of the atmosphere. It's logarithmic, not linear. That's on a "standard day" which is defined as 59F and 29. 92" of mercury (or 10C and 1013 millibars for our metric readers) pressure at sea level. Given standard temperature gradient (2C/1000'), you can calculate the temp at any altitude. Anything different from the standard day and your numbers change. So, on a hotter than standard day, your "density altitude" is higher than normal, meaning you could have the air density of say 5000 at sea level if it's in the 90s (and in practical terms, less air/oxy molecules per cubic inch). Conversely, if it's in the 30s, you have the air density of say -3000' at sea level.

If I'm calculating my range, endurance or performance, I have charts to use based on the standard day. If it's warmer, my performance at altitude suffers. That's engine AND wing, since the wing is dependent on the density of the air, too. On a warmer day, I don't get as much poop (highly technical, almost classified military term there) out of the engines. Yesterday, I did a flight with a takeoff temp of about 32 (at sea level) and we climbed and accelerated like a banshee. I also can't pull as many Gs at altitude (or on a warmer day) as if it's cold or if I'm down lower. The density of the air also affects the liftys (another one of those highly technical terms) the wings produce.

Not sure why you have more trouble catching your breath on colder days at altitude since the air is "thicker". Maybe your lungs just aren't adapted to cold air? It takes me a while to adapt to desert environments where it's so hot. I try to run and I feel like I should call Richard Simmons because I'm such a weakling until I acclimate. If it's cold and I'm at altitude, I adapt more quickly.



[This message has been edited by joel (edited 12-16-2000). ]

 

[Chad Sheets]

Turbine engines to diesel engines... huh? I already know about cool air on turbine engines. I spent my time in the Corps flying around in the United States largest helicopter, the CH53, which is powered by 3 of them, 4 if you count the turbine engine used to start the other 3. Cooler air also makes my drag car pick up a couple tenths. Cooler air also makes my old pulling tractor have more giddy up. High altitude air makes for low power on everything and also will not allow the CH53 to pick up as much weight because the rotor blades are turning in thin air and cant get any lift. What this has to do with a diesel engine, I have no clue? Cool air IS good for a diesel engine guys. My original post states that intake temps between 60-90 degrees are ideal. That is cool air to a""stock"" diesel engine. Naturally the more fuel mods you have, the cooler you can go, say 40-50 degrees. This is all general applicable information. If you are pouring more fuel into the equation, then YES you can run cooler intake air temps... that's a no brainer, but if your engine is stock, cooler intake temps are going to lessen your power output and lessen the amount of fuel burnt in the process.

This debate has taken a wrong turn someplace. The original insight I was trying to give away was that...

A. Ideal intake temps for a diesel engine is between 60-90 degrees.

B. Remove your so called "ram air" systems in the winter to help improve combustion efficiency.

C. For every drop in intake temps by 20 deg, you drop combustion temps by 60 deg at the top of the compression stroke.

"Chad" is not right or wrong. All Chad is doing is taking information not known by many from the diesel testing environment on a big scale and blending it with already established diesel facts from field test and relaying that information here to you. The original author wanted to know the difference between taking air in from under the hood via holes drilled into the stock airbox, or taking air in from outside. Someone stated that under the hood air is hot and therefor ultimately lowers performance. That's when I chimed in to demonstrate A, B, and C above, and from there we dove into all sorts of different situations. In the authors situation with a stock truck (planning on buying doesn't make it modified until the enhancements are added in my book) putting a psychotty system in will not do much more than a stock K&N filter in the airbox, AND with a stock truck the airbox is the better way to go financially and mechanically. Start adding DDIII's, VA's, and PE boxes on the #3 setting and YES the obvious choice is a more freely flowing air system like the psychotty that taps into cooler air environments. With that said is there anyone that doesn't agree with A, B, or C applied to a stock engine?


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Always ready to help!
2000 2500 Red Sport quad cab, 4x4, K&N, DDI's, straight piped, boost, pyro and fuel pressure gages, Hot Power Edge, mean looking set of 33. 5" tires, Snap On diamond tool box, Marine Corps window sticker, Semper Fi!

1972 340 Cuda'. Original tripple Black, 340 car w/air. Good clean car, super stock springs, Weld Prostars, shaker hood, strong 340 with a 727/4000 stahl, 4. 56... . Bombs away!
NRA Life Member. http://www.geocities.com/chadsheets

 

[jkern]

interesting #'s on the intake temp sensor... actually i would have expected higher temps, but with the extreme cold, and that huge intercooler i guess things stay cool. i look forward to hearing more testing numbers!!

the purpose of NOS is just what i was talking about eariler... it is only an oxidizer... just adds lots of oxygen to the engine, therefore you can add more fuel and still get a complete burn. basically that is what our turbos do, they compress the air so that more of a oxygen charge gets into the cylinder to support and facilitate more complete burning of the fuel that is introduced.

anyhow, so i am still wondering... do air box modifications make that big if a difference in performance, and now with some numbers available, do the pschotty and pseudo pschotty systems really work and are they worth the $$$$???

by the way, thanks guys for the replies, this has been a very educational for me as well as others.

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Jeremy Kern
1999 2500HD 4x4 QC,SB, ISB, 5spd, 3. 54LSD, 33x12. 50 cooper STT's Denver off-road bumper with Ramsey RE12000, PIAA series 520, Rancho RS9000's, heavy ft. springs, and a bunch of other little things!

 

[EricBu12]

Chad,
I am in complete Agreement with you.
I am an interstate truck diver (big rig) and I know that the colder air makes for less power. I have a Ram, (see sig. below) and I have seen a 2 to 3 MPG loss on average to the colder air temps. It gets down to 10's and 20's now but can be much colder I was going to take off the horn and cover the hole to the fender with cardboard and have the warmer air from the underhood to make better combustion. My ram is up to 7K miles and from summer to winter, I have noticed a drop in MPG's due to pushing the pedal more to go the same amount as before. also, I have noticed that the grid heater runs more often when it is reved up when cold than Idle. Keeping the warmer air to the engine is the best to make efficient combustion.
Hope I made people think. Cold air is for gassers!! lol
Eric

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2001 QC 2500 4x4 bronze W/two tone Driftwood, 24valve HO 6sp. Westin side bars, fender flares, Spray on bedliner, soon to get shell Painted to match and Bf Goodrich AT Tires

 

[Diesel Freak]

OK here goes. We all know that cold air is denser than hot air we also know that air is also approximately 20% O2 and almost 80% N2 with a trace of argon. What we need to understand here is there is a point of deminishing returns when cooling an intake charge. Energy must be used to raise the intake air temperature high enough to promote proper combustion. If the air is too cold more energy has to be used to raise the temperature for the fuel to ignite. Air below 60 F will preform less efficiently as the temperature drops due to higher adiabatic losses to heat the 80% N2 in the air. Nitrous Oxide (N2O) will only generate more power if there is excess fuel to burn (if your engine smokes) Most engines are factory dyno'd under laboratory conditions if they are not then a calculation is made to correct them where altitude, temperature, humidity, and barometric preasure are taken into account. One last thing. The intercooler on our trucks is there to cool the intake air for full load operations. It can actually be a detrement in extremely cold weather when the engine is not under load. That is why fuel economy drops as the temperature gets really cold and probably one of the reasons my Dad's 1990 12 valver(no intercooler) gets better fuel economy than my 2001 ETH when driven conservatively.
just my $. 02

[This message has been edited by cdaledh (edited 12-17-2000). ]

 

[sport bike]

Did you ever think that the winter mix fuel makes less power.

 

[Scott_Old]

Chad is right to a degree, if your intake air is below a certain point, performance will decreace. But if temps get to high, melt down occurs.
That is why our trucks loose power/MPG in cold ambient temps(more so with winter fuel)
and why we have intercoolers to keep air from getting too hot.
I would like to have alittle more intake heat in this 10-20 degree weather. More power/mpg. Scott

 

[illflem]

We had a heat wave here today,the Chinook winds from the south started blowing,the temp went from 14°to 46°in a couple of hours. Driving the 22 miles RT to town at the hottest part of the day my intake temp varied from 76° to 88°. This was drawing air from the psuedo Physcotty vent cowl location. Highest temps are idling after warm up,lowest at high boost(22 psi). The temp stayed steady at 82° with cruise set at 60 on flat land,still had winter front on. Temps are still running much cooler than I expected,but it looks like the ambient temp has to be below around 30°in order to be concerned about low intake temps.

 

[Diesel Freak]

actually winter mix fuel should give beter economy due to the higher cetane rating. Winter mix diesel fuel is not oxegenated like gasoline is in the winter to reduce CO... alcohol in diesel..... BAD JUJU

 

[drawson]

Ok here is my take on worse fuel economy in the winter. The air is more dense which is hard to push our truck through, so due to more air resistance is some of the lose. I know I idle mine more in the winter and the engine isn't up the operating temps as fast as in the summer. Winter fuel has less BTU than summer fuel. Less BTU = Less MPG.

Bill any pictures of your temp sensor installation?

 

[illflem]

drawson,slipage on ice/snow must also come into the winter time mpg factor.
I'll get some pics and start a new thread over in products/assesories

 

[Chad Sheets]

If you look on Scottys webpage, the guy who has the Psychotty system, he even tells you "that the unit works best on a modified truck.
A stock truck will see a marginal reduction of about 50 to a max of 100F
under hard load. "

Kinda goes hand in hand with what some of us have been saying for a while now.

Scotty has an awesome set up. You will see big differences using it if you have big fuel modification, and little differences with no fuel mods. If you got some hog injectors, and any other electronic fueling box, you need one of these set ups to keep the combustion triange "ballanced".


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Always ready to help!
2000 2500 Red Sport quad cab, 4x4, K&N, DDI's, straight piped, boost, pyro and fuel pressure gages, Hot Power Edge, mean looking set of 33. 5" tires, Snap On diamond tool box, Marine Corps window sticker, Semper Fi!

1972 340 Cuda'. Original tripple Black, 340 car w/air. Good clean car, super stock springs, Weld Prostars, shaker hood, strong 340 with a 727/4000 stahl, 4. 56... . Bombs away!
NRA Life Member. http://www.geocities.com/chadsheets

 

[Chad Sheets]

As for the winter time loss of MPG... people see a loss of MPG in the first cold days of fall, long before winter blend is available. As the day heats up, everything comes back into range. Thats why I got better MPG driving to work on warm (mid 70's) fall days, compared to the drop in MPG at night during cool (low 50's) fall night time drives.

 

[Mr. C]

So after reading everything everone had to say on the subject would it be fair to asume that a air flow blocking device in the winter will give better operating efficency due to an increased intake temperature countering the effects of the over effecent charge air cooler durring cold weather opperation?? Better fuel economy??
Wow ,my head hurts. #ad